[Elecraft] AC hum on tune

[Julian, G4ILO]

W8JI wrote:
> 
> 
> Sam,
> 
> It is common for me to hear hum or buzz on local receivers 
> very near a transmitter. Even on perfectly clean 
> transmitters unless I use a line tap to sample signal all 
> sorts of stuff mixes in. I've never really looked into why. 
> My guess would be it is some nasty multipath being modulated 
> by something. Just a guess.
> 
> I'm not saying you don't have hum, but just cautioning you 
> to be careful when listening on a local receiver near a 
> transmitter. I can replicate hum on my shop receivers even 
> with a very clean transmitter on the bench.
> 
> That aside, did you try disconnecting everything except the 
> K3 antenna and power supply?
> 
> Switching supplies do not normally cause 60 or 120 Hz 
> problems.
> 
> 73 Tom 
> 
> 
> 

I agree with Tom. I have wasted a lot of time trying to eliminate a non
existent problem caused by local monitoring.

Obviously as you have had reports from other stations there must be
something wrong but I don't think the K3 is particularly prone to
transformer induced modulation. Mine sits right next to a Diamond GSV3000
power supply which has a huge great transformer in it and I have never had a
problem.

-----
Julian, G4ILO. K2 #392  K3 #222.
* G4ILO's Shack - http://www.g4ilo.com
* KComm - http://www.g4ilo.com/kcomm.html
* KTune - http://www.g4ilo.com/ktune.html

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